Hydraulic mining process



June 26, 1962 A. F. JOHNSON 3,041,053

' HYDRAULIC MINING PROCESS Filed April 22, 1959 SURFACE HYDRAULIC SOIL GIANT k MUD STREAM OVERFLOW MOBILE PUMP REMOVAL SUMP OF CONTAINED VALUABLE MINERAL \UNDERFLOW w T R A E OVERSIZE SIZE WASTE CLASSIFIER /UNDERSIZE REAGENTS GANGUE WASTE) QANGUE DEWATERING MINERAL m fi QI L w sTE v cE CONCENTRATOR CONCENTRATE FRESH WATER INVENTOR ARTHUR E JOHNSON BYfi Q EMMA 77101.17! 7 4mm T 9 ATTORNEYS Uite Sttes This invention relates to the mining and concentrating of alluvial material, such as surface soil, sand, gravel or soil that is so loosely consolidated that it can be broken up and moved by a stream of high pressure water such as is being used in hydraulic mining with apparatus known as an hydraulic giant, and provides an improved process for hydraulic mining in which the water is used cyclically.

My invention provides a process for directing the water and its contained earth removed by the hydraulic stream or jet into a sump for the separation of the water from gravel and rocks, and the return of the water to the hydraulic giant for re-use cyclically in removing additional earth. The sand and gravel which settle in the sump are concentrated by any suitable means and then subjected to treatment for the recovery of the contained minerals, and the water from these concentration and recovery treatments is also returned to the hydraulic giant for re-use.

Hydraulic mining is one of the cheapest methods of mining surface materials, but its use has been restricted on account of several disadvantages. It requires large amounts of water available, preferably from a source permitting high heads, and such Water is frequently not available in sufficient quantity to satisfy present mining techniques. Also, the large amount of resulting waste Water has contaminated streams because of the lack of the run-away of the once-used water.

My process permits cheap mining by the hydraulic method without consuming large quantities of fresh water and without contaminating streams with debris. My process produces a concentrate of valuable minerals from loose surface formations containing these at the time and place Where the hydraulic washing is conducted. Whereas hydraulic mining requires 2 to 5 times as much fresh water as the earth to be washed, my process uses only a fraction of a ton of water for each ton of earth washed so that the resulting washed-out earth after the separation and beneficiation treatments is discharged in a moist condition that does not contain enough water to carry debris into streams and contaminate them.

There are further advantages to my process which will be better understood after considering the accompanying drawing which illustrates diagrammatically in a flow sheet and arranged of apparatus for carrying out a process of my invention. A typical process of the invention will be described with reference to the drawing.

The hydraulic giant, such as is commonly used in hydraulic mining, is mounted on a tractor, endless tracks or other mobile unit and is usually placed to remove the loose formation from a hillside, gulch or flat area. A mobile sump, preferably mounted on the same tractor as the hydraulic giant, is provided for the purpose of catching the stream of mixed water and solids resulting from the operation of the hydraulic giant.

In the sump the gravel and rocks are separated and the overflow water is passed to the pump which supplies the stream or jet issuing from the hydraulic giant. The sand, gravel and other fine material which settle in the sump may be beneficiated by the use of gravity and momentum concentration, and, if gold be present in the formation, mercury may be added in the bottom of the sump to collect the gold in these operations. The overflow water from the sump may be treated by flotation or other minatcnt eral separation methods as the overflow water will, in many cases, contain mineral-bearing slimes or mud which will not readily settle in the small mobile sump. Suitable chemicals or reagents may be added to the water or the gravity apparatus to enhance the beneficiation process employed. For example, lime, pine oil and xanthate may be introduced into the water to aid the flotation process used on the Water stream or pulp stream of water and sand so that sulfides may be separated from the bulk of gangue and from the water.

The sump not only has an overflow means such as a weir or gate but an underflow means. The underflow from the sump containing water and entrained materials of various kinds and sizes is passed to a classifier. It is the object of my invention to discharge the solids from the process in as dry a state possible to reduce to a minimum fresh water used in the process. To this end, I may use a filter to separate the water or water-solids mixture. However, I usually prefer merely to remove all possible water by compacting the solids with vibration as permitted, for example, by conveying the waste solids slightly uphill or up an inclined vibrating conveyor which may be actuated by a vibrating mechanism. In such an inclined vibrating pan feeder the water is extracted from the solids by compaction and flows countercurrent backward into the bowl of the feeder while the solids are propelled forward up the inclined of the feeder and discharged as waste. Within such a feeder solids 'may be classified according to size by grizzly bars or screens so that the finer material in the bottom of the vibrating conveyor may be subjected better to gravity concentrating methods. For example, the bottom of the vibrating conveyor may communicate with or be a part of a jig which settles into a hutch, heavy minerals such as gold, tungstic oxide such as wolframite, cassiterite, zircon, sulfides of metals or heavy oxides not mentioned above. Likewise, the bottom of the vibrating feeder may communicate with a flotation machine which subjects the classified solids to beneficiation by mineral flotation. In any case I endeavor to keep the beneficiation apparatus compact so that it can be carried in the mobile unit or units along with or near the hydraulic giant that mines the soil and re-uses the water.

Water which recirculates in the process may be partially clarified by centrifugal devices and unless filtered will contain some slime. This slime content is not a disadvantage, but may be an advantage since it gives the jet greater specific gravity than clear water and hence greater striking power in disintegrating the soil bank being mined, and greater carrying power for delivering solids to the sump since rocks do not settle in a pulp of slime as quickly as they do in clear water. In my process I prefer to add the fresh Water required for make-up in the gravity concentrating device. When a jig constitutes the gravity concentrating device, I add the water in the hutch of the jig so that the concentrated mineral is washed as clean as possible.

'I claim:

1. The process of mining loose earth formations with a stream of high pressure water from an hydraulic giant which comprises collecting the resulting mixture of water and suspended solids in a sump, removing from the sump an underfiow and an overflow, beneficiating the underflow to remove valuable minerals and recover Water which water is combined with the sump overflow and pumped to the hydraulic giant for re-use in said mining.

2. The process of claim 1 in which the beneficiation includes froth flotation and the water therefrom with its contained dissolved reagents is used over and over again as the Water is used over and over again.

3. The process of claim 1 in which the re-used water 3 is subjected to a process for the removal of contained valuable mineral continuously.

4. The process for recovering minerals by hydraulic mining which comprises providing a movable hydraulic giant and attached sump, removing loose earth with a water jet from the hydraulic giant, directing the Water with its contained earth into the sump, separating from the water a major portion of the earth as oversize Waste material, removing from the sump water and an undersize portion with its contained minerals, beneficiating the 4 undersize portion with its contained minerals and recovering the minerals therefrom, and returning the water to the hydraulic giant for a repetition of the operation, and from time-to-time moving the sump and hydraulic giant to a closer position to the formation being mined.

References Cited in the file of this patent UNITED STATES PATENTS 932,037 Low Aug. 24, 1909 

1. THE PROCESS OF MINING LOOSE EARTH FORMATION WITH A STREAM OF HIGH PRESSURE WATER FROM AN HYDRAULIC GIANT WHICH COMPRISES COLLECTING THE RESULTING MIXTURE OF WATER AND SUSPENDED SOLIDS IN A SUMP, REMOVING FROM THE SUMP AN UNDERFLOW AND AN OVERFLOW, BENEFICIATING THE UNDERFLOW TO REMOVE VALUABLE MINERALS AND RECOVER WATER WHICH WATER IS COMBINED WITH THE SUMP OVERFLOW AND PUMPED TO THE HYDRAULIC GIANT FOR RE-USE IN SAID MINING. 